Circumcision rates for newborn boys in NSW have jumped by more than 30 per cent in the past two decades, and there is now a call for the procedure to be reintroduced in public hospitals.

Sydney University professor of medicine Brian Morris claims the latest evidence shows the operation is ''equivalent to childhood vaccination'' and it is ''unethical'' not to offer the procedure to all parents as a matter of routine.

He has written to NSW Health Minister Jillian Skinner urging her to lift the ban on elective circumcisions in public hospitals, claiming the cost savings in diseases and adverse medical conditions will be ''massive''.

About one in six - or 8100 - infant boys in NSW were circumcised in 2012, more than twice the number of any other state. It is an increase from one in eight in 1994, despite the procedure being banned in public hospitals since 2006, unless medically necessary.

Paediatrician Howard Chilton says a greater acceptance of ''health advantages'', such as reduced risk of urinary tract infections, means more parents are choosing to circumcise boys, usually before they are six weeks old.

''Twenty years ago, circumcision polarised people but that seems to be evaporating,'' he said. ''Now about 30 per cent of newborn boys I see are circumcised. Usually it's for cultural or health reasons and because dad had done it and the parents like the aesthetics.''

But he said the health benefits are not so ''overwhelming'' that it justifies interfering with the ''baby's right to have an intact body. I don't interfere with the parents' decision''.

Professor in epidemiology at the University of NSW Andrew Grulich says a shift in Sydney's ''cultural mix'' since the 1990s, including the growth of the Muslim community, may account for some of the increase.

''There has also been a lot more discussion over the past decade about the health benefits,'' he said.

According to a review of studies, published in Mayo Clinic Proceedings, removing the foreskin at birth outweighs the risks by 100 to one, with a claim the procedure protects against urinary tract infections, prostate and penile cancers.

Professor Morris is the lead author of the review and he says that, over their lifetimes, half of uncircumcised males will contract an adverse medical condition caused by their foreskin.

But Dr Chilton says the figures can be deceptive, particularly in penile cancer where the risk is less than one in 100,000, so any increased chance is very small.

And the Royal Australasian College of Physicians' policy maintains the medical benefits ''do not warrant routine infant circumcision''.

Maroubra finance executive Stefanie MacDonald had her son James circumcised when he was five weeks old after debating the procedure throughout her pregnancy.

''My husband and I swayed back and forth on it for so long,'' she says. ''It wasn't for any religious reasons. Even though there is no conclusive proof, there has been talk about increased risk of infections so we just wanted to stamp that out.''

The procedure cost about $800 and the Medicare rebate was about $200.

''Some of my friends questioned me doing it. But in the end I'm happy with what we've done.''